feat: Add unit tests and fakes for Crestron environment and data store

- Introduced `FakeCrestronEnvironment` and `FakeEthernetHelper` for testing purposes.
- Implemented `InMemoryCrestronDataStore` to facilitate unit tests for data storage.
- Created `DebugServiceTests` to validate the behavior of debug-related services.
- Added project files for unit tests targeting .NET 9.0 with necessary dependencies.
- Developed production adapters (`CrestronConsoleAdapter`, `CrestronDataStoreAdapter`, `CrestronEnvironmentAdapter`, `CrestronEthernetAdapter`) to interface with the Crestron SDK.
- Updated `Debug` class to utilize injected service abstractions instead of direct SDK calls.
- Enhanced `ControlSystem` initialization to register service adapters before usage.

src/PepperDash.Core.Abstractions/ICrestronConsole.cs

@@ -0,0 +1,32 @@
+namespace PepperDash.Core.Abstractions;
+
+/// <summary>
+/// Abstracts <c>Crestron.SimplSharp.CrestronConsole</c> to allow unit testing
+/// without the Crestron SDK.
+/// </summary>
+public interface ICrestronConsole
+{
+    /// <summary>Prints a line to the Crestron console/telnet output.</summary>
+    void PrintLine(string message);
+
+    /// <summary>Prints text (without newline) to the Crestron console/telnet output.</summary>
+    void Print(string message);
+
+    /// <summary>
+    /// Sends a response string to the console for the currently-executing console command.
+    /// </summary>
+    void ConsoleCommandResponse(string message);
+
+    /// <summary>
+    /// Registers a new command with the Crestron console.
+    /// </summary>
+    /// <param name="callback">Handler invoked when the command is typed.</param>
+    /// <param name="command">Command name (no spaces).</param>
+    /// <param name="helpText">Help text shown by the Crestron console.</param>
+    /// <param name="accessLevel">Minimum access level required to run the command.</param>
+    void AddNewConsoleCommand(
+        Action<string> callback,
+        string command,
+        string helpText,
+        ConsoleAccessLevel accessLevel);
+}